This study involves an objective assessment and description of one hundred children diagnosed as having mild, moderate or severe hemophilia. Basic demographic information, family psychiatric history, and measures of level of knowledge concerning hemophilia will be collected. The psychosocial impact of the disease upon the family as a system will be examined with regard to family environment, attitudes and roles. Incidence and severity of anxiety, depression, drug and alcohol abuse and other psychiatric symptomatology will be assessed for each family member. In addition, we will evaluate responses of patients and their families to the development of an inhibitor response in the identified patient. It is hypothesized that there will be greater evidence of psychological disturbance in hemophilic children as compared to control siblings, and that extent of knowledge about the disease as well as severity of hemophilia will be significantly related to level of psychological adjustment in both the identified patient and his parents. The answers to these and to other hypotheses included in this study will have important implications for the treatment of hemophilic patients. Data collected here may well suggest that effective treatment for this disease must include consideration of both psychological and family structure variables.